The present invention relates to containers and more particularly to a new and novel easy opening end closure for a container and to the method for forming the same.
Heretofore it has been common practice to form easy opening end closures by scoring the end panel to define a removable panel portion. A metal tab for separating and removing the removable panel portion is attached to the latter by a rivet integral therewith.
By the present invention it is proposed to provide an easy opening end closure or unit for a container including a plastic tab which is fastened to the removable panel without requiring a rivet or the like. The plastic tab is attached to the panel of the end unit in a manner such that it separates a closure portion from the panel and forms a seal along its line of separation. The tab remains attached to the closure portion when the latter is displaced to provide a pour opening in the end closure.
The end closure of the present invention comprises generally a plastic strip overlying a metal panel and which is sealingly seated in a slit formed by forcing the plastic through the panel to cut the panel to define a closure portion. In one form of the invention the closure portion is defined by a continuous cut line or slit. The plastic strip is disposed in the slit and embraces the edges about the slit and the closure portion to retain the latter on the panel. The plastic strip includes a finger grip portion which overlies the panel. Upon gripping the finger grip portion and applying an upward pulling force, the plastic in the slit is separated from the edge on the panel and remains attached to the closure portion as the latter is separated from the panel to provide an opening. The slit is preferably formed so that the marginal edge portion of the panel bounding the opening is turned downwardly. Thus upon separation of the closure portion, the raw edge bounding the opening is not exposed. This reduces the possibility of injury by cutting or the like.
In another form of the invention the closure portion is defined by a discontinuous slit in which the plastic is embedded. The unslit portion serves as a hinge about which the closure portion may be turned to press it into the container.
The above described easy opening structures are constructed by a novel method comprising generally the steps of placing a strip of plastic in a die including a punch for blanking the strip of plastic material and a forging punch. The plastic strip is struck by the forging punch so as to displace and force the plastic against a sharp cutting edge to sever the panel and form a slit into which the plastic is embedded. The slit with the plastic embedded therein defines a closure portion which is displaced out of the plane of the panel to provide a pour opening in the panel.